I LOVE your first sentence. You've established a nice voice right away.

I kinda wanted to see a name in the second sentence; someone specific to hang this poetic emotion on. I think that's an artifact of Authoress' masochistic sense of humor, though. (Two sentences? Only TWO? And I thought 250 words was bad! ;-) )

"Instead of springing eternally, hope trickled, drop by drop, until it finally swelled into certainty. Three more days, and she would be safe."

I'd keep reading. I agree with Raylynne about the new twist on the phrase -- it suggests that this POV character is someone who sees things a little differently, and that we'll hear about her unsafety in an intriguing way.

I’m not sure the combination of cliché and its opposite works with the more modern phrasing of the second sentence. I think it would be more powerful, and more gripping, if you just started with the second sentence.

I'm not sure. I like your wordplay, but I feel torn by the certainty, and then the uncertainty implied in that in three days she would be safe. That seems to mean that at that moment, she is unsafe, which doesn't feel very certain.

Very, very interesting. I like it, and I like the whole idea behind it. This sets me up for a lofty, poetic style story though - the kind that is well written enough to not be dismissed as "full of itself," but still fairly close to that edge. If that's what you're going for, you've got it nailed. Pretty cool if you ask me.